Measuring and testing – Test stand – For engine
Reexamination Certificate
1999-07-06
2001-02-13
Moller, Richard A. (Department: 2856)
Measuring and testing
Test stand
For engine
Reexamination Certificate
active
06185995
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to methods and apparatus for testing for the proper assembly of components of apparatus having moving parts. More particularly, the invention pertains to methods and apparatus for determining the proper assembly of automotive engine blocks, including the internal moving parts of such blocks.
While moving down an assembly line, automotive engines may be subject to assembly errors, either by human operators or by automated equipment. Traditionally, two of the most commonly encountered assembly errors for engine components are reversed piston heads and missing connecting rod bearings.
FIG. 1
depicts the cross-section of an engine block
100
showing a crankshaft
106
having a center line of rotation
104
and the connecting rod
108
and its associated piston head
110
for one cylinder
102
of the engine. If piston head
110
is installed incorrectly- that is, upside down, then head
110
will lie at an angle to the longitudinal center line of the cylinder, thereby creating a “slap” condition which is obviously detrimental to proper functioning of the engine once it is fully assembled and started. The slap condition arises from head
110
improperly contacting the cylinder wall at points
111
and
112
.
Similarly, if during the assembly process , a bearing between crankshaft
106
and connecting rod
108
is omitted, connecting rod
108
and its associated piston head
110
will not operate as intended. Rather pronounced knocking vibrations will result from the connecting rod having too much “play” during its stroke, due to the absence of the bearing.
In conventional assembly processes, assembly errors such as those discussed above have been discovered either “the hard way” by starting the fully assembled engine and suffering the consequences, by use of complicated and expensive optical inspection systems, or by labor-intensive manual inspection.
Therefore, there is seen to be a need in the art for an automated, yet relatively simple method and apparatus for determining whether proper assembly of a device having moving internal parts, such as an automotive internal combustion engine, has taken place.
SUMMARY OF THE INVENTION
Accordingly, a plurality of vibration sensors are arranged in a predetermined positional pattern in contact with a device under test. The output of each of the sensors is electrically coupled to a computing element. A coupling device couples a source of motive power so as to cause movement of assembled movable parts within the device. While the source is moving the movable parts at a predetermined rate, vibrations in the device under test are converted to electrical signals by the array of sensors and forwarded to the computing element for conversion into digital signatures. The computer utilizes a method to analyze the digital signatures to determine whether the engine has been assembled correctly. If an assembly error is detected by the computing element, the method functions further to identify both the type of assembly error and the location or locations within the device where the assembly error has occurred.
REFERENCES:
patent: 4730484 (1988-03-01), Olschefski
patent: 5392642 (1995-02-01), Tao
patent: 5421199 (1995-06-01), Himmler
patent: 5511422 (1996-04-01), Hernandez
patent: 5517858 (1996-05-01), Matsuzaki et al.
Kovacs, II Stephen F.
Rucha Robert J.
ABB Flexible Automation Inc.
Harness & Dickey & Pierce P.L.C.
Moller Richard A.
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